Godspeed
by liketolaugh
Summary: Sebastian thinks that Agni is perhaps the most admirable human he's met in over two thousand years; Agni thinks that Sebastian is more than he could ever be... and has room to be better still, if he tries. (A relationship told in kisses.)


**A/N: Hey! I haven't been in Kuroshitsuji in a while, hm? This was originally a set of prompt responses on Tumblr, so they don't flow together as well as I'd like, but I thought I'd post it anyway (despite the rarepair, hehe...) Enjoy!**

 **Title: Godspeed**

 **Author: liketolaugh**

 **Rating: T**

 **Pairings: Sebastian/Agni**

 **Genre: Romance**

 **Warnings: Slight AU**

 **Summary: Sebastian thinks that Agni is perhaps the most admirable human he's met in over two thousand years; Agni thinks that Sebastian is more than he could ever be... and has room to be better still, if he tries. (A relationship told in kisses.)**

 **Disclaimer: Sadly, Black Butler is not mine.**

* * *

The door was locked, but either one of them could force it open.

The closet was cramped, but there was enough room for Agni to pull away if he wanted, rather than leaning close and bracketing Sebastian's body between his arms.

The idiot servants were chanting 'kiss, kiss, kiss' outside the door, but only Sebastian could hear that.

Sebastian's eyes were widened slightly, probably reflecting the small bit of light coming in through the door, his head tilted back to look at Agni, who seemed… transfixed, and a little embarrassed.

They were pressed very close together; the spiritual burn of Agni's blessed arm prickled Sebastian's skin through both their layers of clothing. Sebastian was off-balance, elbows against the wall behind him to keep him upright.

"Your colleagues are quite mischievous," Agni breathed, with a hint of a nervous laugh.

"So they are," Sebastian agreed, keeping his voice even. Despite the lack of light, he could see Agni perfectly. "They mean well, I suppose."

"Of course," Agni agreed, and then he leaned down, his mouth just missing Sebastian's and catching the corner. Smiling, Sebastian turned into it, making it a proper kiss and deepening it slightly.

Outside - they must have been watching through the crack in the door - the servants burst into cheers, loud enough for even Agni to hear. He reeled back, eyes widening in mortification.

In the moment before the servants opened the door, Sebastian laughed.

* * *

Agni's grin stretched all the way across his face, warmth and laughter bubbling up in his chest. Sebastian, oblivious to this, cooed softly at the armful of kittens that were crawling up his arms, hanging off the woolen sleeves, while their mother curled up in Sebastian's lap, dozing.

Sebastian liked to play at indifference, but at times like this, Agni found that it was easy to believe him to be just another man, aloof from nothing. An unrestrained smile curved Sebastian's mouth, and one of his hands moved swiftly to catch a kitten that had started to slip from his elbow.

One of them started to claw its way up Sebastian's shirt, reaching his neck and drawing a small amount of blood there with its tiny claws as it tried to bat at his hair.

"An enterprising one, I see," Sebastian laughed, unmistakably ruby eyes glimmering in merriment, head tilting slightly away from the calico kitten but otherwise unbothered.

Agni chuckled softly, reaching over to rescue Sebastian's earlobes from the tiny beast. He cupped it between his hands and lifted it gently away, and it mewed its surprise but then was distracted by a stray thread on the bandages around his hand. "A litte hunter-to-be," he agreed, smiling at Sebastian.

He never saw Sebastian as happy and as carefree as he was when playing with cats, and it filled him with a bubbly delight that he didn't bother to keep in check.

Without a moment's thought, he leaned down slightly to catch Sebastian's mouth in a brief, chaste kiss. Sebastian's mouth opened a little, a quick exhale of surprise leaving his mouth, and Agni pulled away, still smiling.

Occasionally, Sebastian would give Agni a look like he believed Agni to be an alien; Agni probably shouldn't find it as charming as he did. He did anyway.

This was the face Sebastian wore now, and after a moment, he blinked and shook his head, and then smirked at Agni, a faint flush of color creeping across his cheekbones.

"And yet it wasn't the kitten who pounced," he teased, focused, just for a moment, on Agni instead.

Agni rocked back on his heels and laughed, little kitten still cradled gently in his hands.

* * *

It was a bad day all around. Ciel had been wracked by nightmares the whole night long, and it made him cranky and jumpy that entire day; that made the servants worried, so they tried harder and more frantically and messed up more, the disasters worsening and increasing in frequency as the day went on and they got more upset. Soma had run around trying to cheer Ciel up, and at one point (when Soma attempted an ill-advised hug) Ciel had nearly reduced the young prince to tears.

Agni had been working hard to maintain the peace all day, making food and sweets and comforting his prince, as well as helping Sebastian to repair the servants' botched work and keep them on track for a meeting with Randall which they had nearly had to cancel, the household was such a wreck. (Emotionally, obviously. Sebastian could have fixed a physical wreck with ease.)

Even Sebastian was irritable, fire on his tongue and temper worsening over the course of the day, the shadows of the house beginning to ripple and pulse ominously as he tried desperately to keep a lid on his more predatory instincts (for the house so seemed like a den of prey animals, tonight.)

At the end of the day, Agni looked exhausted, movements slow and almost clumsy, after the other servants and the two fussy masters had gone to bed. The two of them were quiet as they did the final washing up of the day, Agni's shoulders in an uncharacteristic slump.

The silence maintained until the plate in Agni's plate cracked, a gunshot in the late-night quiet. And Agni dropped the pieces back into the water, blood welling up where the shard had cut into his unbound hand, and dipped his head.

"I apologize, Mister Sebastian," he said, voice hoarse and barely audible. It shook subtly. "That was unforgivably clumsy of me."

Sebastian often forgot how difficult it was, for humans with abnormal strength. He himself, after all, was many centuries too old to be making such errors.

"It has been a long day," he said, shaping his voice into something as close to gentleness as he could manage. "You should sleep, Mister Agni, or you will not be able to function tomorrow."

Agni laughed, soft and a little bitter. "You seem fine," he said, voice quietly self-incriminating.

I do not require sleep, Sebastian did not say. "If it would make you feel better about it, you may wake the young master and prepare breakfast. But I ask that you sleep now. I will finish up tonight."

Agni still hesitated, and Sebastian leaned forward, sliding his lips over Agni's for a brief but heated kiss before he pulled away, keeping close. For a moment, their eyes were fixed on each other, nearly spellbound, before Sebastian pulled away.

"Please," he said, the word almost unfamiliar.

Agni sighed, and gave Sebastian a wan but grateful smile.

"Thank you, Mister Sebastian," he said. "I will take care of your duties in the morning. I promise."

Sebastian nodded and, as Agni started to pull back, he turned his attention to his work, tracking Agni absently as he wiped his hands off, and then headed straight to bed, almost collapsing into it without even undressing.

* * *

Sebastian's kiss was long and lingering, like only a few of their kisses ever were. And when he pulled away, his russet eyes were dark with melancholy, his mouth pulled into a thin, unhappy line.

Startled, Agni reached up to brush his fingers across Sebastian's jawline. "What is wrong, moonlight?"

Something flickered in Sebastian's eyes at the pet name, but the shadow didn't leave. Instead, he tilted his head and studied Agni like an alien organism, like something beautiful and fleeting and sad.

"I would wish to take you home with me," Sebastian murmured, thoughtful and soft, one hand moving to brush fluidly down Agni's forearm to the curve of his hand, "but you do not belong there."

"Sebastian…?" Agni was lost.

Sebastian shook his head, and then pressed another kiss on Agni, a swift one on his cheek. "It is nothing, Agni. Just an idle thought."

Agni was not reassured, but Sebastian smiled at him then, a small but rare and treasured thing, and Agni smiled back and a moment later, they had returned to work.

* * *

Grelle has seen thousands, hundreds of thousands, maybe millions of human lives play before her eyes. She was rarely moved by their contents anymore; it just made her job harder.

A life turned around, spent repenting for the sins of his youth and in complete devotion to a single child? Impressive, Grelle had to admit, but not 'impactful.' Not what Grelle was looking for.

She lifted the stamp, and- hesitated.

Grelle had seen nothing extraordinary about Agni's life. Nothing, except- Sebastian, listening to his advice, taking it seriously, and treating the human man with a shockingly genuine regard. Even now, he was holding onto him, face melancholy.

Impressing a devil, one who Grelle could tell was clearly an 'older man,' was not an easy thing to do. And Grelle was suddenly, avidly curious.

For the first time in decades, Grelle switch implements, and scribbled across the page, DENIED.

In Sebastian's arms, Agni began to breathe again.

Grelle sighed. Well, she'd never claimed to be a perfect reaper.

* * *

Sebastian had sensed Grelle's presence when they entered the townhouse, but aside from an unfamiliar chill of dread, he hadn't acknowledged the reaper. There were more pressing matters.

He was still holding onto Agni's body when he tasted the abrupt return of Agni's saccharine soul, and Agni began to breathe again, eyes even fluttering open as wounds began to seal, falling from 'fatal' to 'severe.'

Sebastian froze.

"Seba-" Agni choked out, eyes not quite focusing. "Seba… stian, my prince-"

"He's fine," Sebastian said quietly; he was certain of it, could hear Soma's breath, only slightly labored. "You did very well, Agni."

"I-" Agni seemed confused, and Sebastian leaned down and pressed a soft kiss to Agni's lips, just for a moment and somehow more intimate than anything else he'd ever done.

"We have a god to thank tonight, Mister Agni," Sebastian said. "But for now- rest. I will protect your prince."

Agni relaxed, and his eyes closed.

* * *

Soma didn't leave Agni's side the entire time the man was unconscious. For three days he ate and slept and stared anxiously at Agni's face by his khansama's side. His own injuries stood out starkly, a bandage around his hand and a bruise on his head, but they may as well have not existed, for all the mind he paid them.

Ciel had returned to the townhouse to continue work on the case, with his servants on full guard, but, tellingly, Sebastian spent most of his time at the hospital, minding the young prince and keeping a watchful eye on his… friend.

("A twin?" Soma had spat, disbelief and betrayal and fear crawling on top of each other in his voice. "Ciel, you have _never_ mentioned- how can I believe-" But Ciel reached up and untied his eyepatch and Soma fell silent, chest still heaving.)

Soma was asleep the first time Agni woke, eyes not opening all the way and tongue flicking out to lick undoubtedly dry lips.

Sebastian responded in a moment, driven by a motivation he didn't immediately recognize but labelled as 'duty.' He tipped a small cup of water into Agni's mouth, waited for him to drink, and then began speaking as he turned away, voice brisk.

"You have been unconscious for three days. Prince Soma is asleep to your right, within reach if you wish. He has slept an adequate amount and has only missed two meals, both two days ago. You are currently stable and will be able to leave the hospital in perhaps a few weeks to a few months."

He finally turned back to look at Agni. He looked a little more awake, but comprehension was slow to spread across his face. His skin was still too pale and sallow with loss of blood, expression dull and beginning to pinch as pain set in through the haze of opiates.

He looked fragile; he looked human.

Sebastian kept his expression neutral.

After a few moments, Agni gave him a weak, strained smile, and lifted a shaky hand, which wandered slowly through the air until it unerringly found Soma's head, pillowed in his arms on the side of the bed, and rested there. Agni relaxed.

Sebastian cleared his throat, uncomfortable. "The young master has asked me to mind you and your prince until you are reasonably able to do so yourself," he said.

A dozen expression flickered across Agni's face, and he smiled again and coughed.

"Th-" Agni grimaced, closing his eyes and furrowing his brow. "Th-thank… you."

Sebastian nodded once, and then said, "Of course." (He had more to say, but found that all the words were in Latin.)

Agni opened his eyes again, and they seemed to linger overlong on Sebastian's. Sebastian had the sudden, unnerving feeling that Agni knew something he should have no way of knowing.

Agni smiled again. Sebastian did not know where he'd gotten the energy for it; he never knew where he did.

Then Agni's eyes closed, long enough that Sebastian nearly believed him to have fallen asleep. And then he whispered, hoarse and choppy, "K-ki-kiss me?"

Without a moment's hesitation, Sebastian leaned down and pressed his lips to Agni's. When he pulled away, Agni was asleep.

His right hand never left Soma's head.

* * *

The day after Ciel's death, after Sebastian had ensured his affairs were settled like a good butler should, Sebastian appeared outside Soma and Agni's home.

Agni had long recovered by then,though he still moved gingerly at times and would never be as fast or as sturdy as he once had been, as irrevocably human as he was. He and the prince had moved into their own home at Ciel's pointed encouragement, away from direct and obvious association with the Phantomhives, though they had continued helping anyway.

Even after the disaster with Ciel's twin brother, they had remained kind and loyal allies. Friends.

Of course, now…

Sebastian knocked briskly on the door, and it was Agni who answered - late enough for Soma to be asleep, too early for Agni to be finished for the day.

"Mister Sebastian," Agni greeted, warmth in his voice, though his surprise was clear. "What brings you here at such a late hour?"

The words in Sebastian's mind were in Latin again.

He bowed at the waist and spoke to the ground.

"This is the last time you will see me, Mister Agni. It has been the utmost honor to know and work with you."

He heard Agni inhale sharply and straightened up, meeting Agni's gaze evenly. Agni's eyes were wide, one of his hands up almost to his mouth.

"What have you done?" Agni whispered, tears already rising to his eyes. He had always been far, far too perceptive, Sebastian thought- and he and Soma knew more of them than nearly anyone.

Sebastian smiled; it felt strange on the mouth of his human form. "You know that I am not as good a man as you are," he reminded the khansama gently. And then, unbidden, "I'm sorry."

To cover up that last, Sebastian stepped forward and pulled Agni into a kiss, deep and hot and slow. His gloved hand cupped the back of Agni's head, pulling it down while his own head tilted up, and after a moment, Agni reached up to sink his fingers into Sebastian's tailcoat and responded in kind, seeking and desperate. (He already knew what was coming.)

They parted at the same time, still holding on and far too close together. Tears were spilling down Agni's cheeks now, and something in Sebastian's chest clenched. He looked _crushed._

He saw Agni swallow, falter, and then speak.

"I-" and then, "My prince," and then "Lord Ciel-"

He stopped. Sebastian remained silent and motionless. Agni swallowed again, close enough for Sebastian to feel, eyes never leaving the devil's.

"It is never too late to be a good man," is what he settled on. And then fire suddenly burst across his eyes, his hands tightened enough to tear the fabric of Sebastian's coat. "No matter what you do, it is _never too late!_ Do you understand me, Sebastian?"

Sebastian closed his eyes and tilted his head, forehead pressing to Agni's cheek.

"Grelle spared your life that day because he knew I found you extraordinary," Sebastian said quietly. "To a god of death, that means something very particular." A pause. Agni's grip tightened, if possible, even further. "Leave your mark on this world, Mister Agni. I believe you can." Another pause. "I will remember."

Just as Agni's chest started to shake in the first sob, Sebastian let go of his bound human form, and let his misty true one dissolve into the night shadows.

A full moon gleamed solemnly above.

* * *

 **Thank you for reading, and please review!**


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